Travelers wait in line at a security checkpoint at La Guardia Airport in New York Wednesday. Millions of Americans embarked on their Thanksgiving travels on Wednesday with security in airports, at New York City's parade festivities, and other venues expected to be heightened amid jitters after the Paris attacks last week. Photo: REUTERS

Given the high volume of travel this Thanksgiving, travelers should brace themselves for delays. This holiday weekend will see record rates of travel, according to an AAA report.

About 46.9 million people will travel this Thanksgiving weekend -- the highest number since 2007 -- with more than 3.6 million people flying during the holiday.

Some flyers may see more headaches than others. Those leaving from or arriving at Chicago’s O’Hare International Airport, the busiest U.S. airport, should anticipate delays. More than 40 percent of flights were delayed during Thanksgiving week over the last three years, according to analysis from AirHelp.

Some of the other worst airports for delays were Denver International Airport in Denver, Colorado; Metropolitan Oakland International Airport in Oakland, California; and Orlando International Airport in Orlando, Florida. Travelers at the three airports experienced some of the highest rates of delays, with more than 25 percent of flights not departing on schedule, according to the Department of Transportation. The study looked at the travel period spanning Monday through Sunday of the Thanksgiving holiday week.

If you have a flight booked from Santa Barbara to San Francisco, you may also want to brace yourself. The route from Santa Barbara Airport to San Francisco International Airport was the most delayed route last year. The average delay was about 45 minutes. Other flights into San Francisco from Denver, Colorado, and Newark, New Jersey, also saw higher rates of delays last year.